To defeat the Celestial in level 1 of LEGO Marvel Super Heroes 2 wait for the Celestial to hit the broken down ship. Then use Star-Lord to build a sling for a gravity mine:

To defeat the Celestial in level 1 of LEGO Marvel Super Heroes 2 build a sling for a gravity mine.

Go over to the sling and shoot the gravity mine at the Celestial. Jump into the ship and shoot at the green circle on the hand of the Celestial:

To defeat the Celestial in level 1 of LEGO Marvel Super Heroes 2 shoot at the green circle on the hand of the Celestial.

Go over to the hand of the Celestial and stand on the button:

To defeat the Celestial in level 1 of LEGO Marvel Super Heroes 2 stand on the button on the hand of the Celestial.

Switch to Drax and climb up to the Celestial. Jump from the ship to the shoulder of the Celestial and punch the glowing box. Go into the box and turn the wheel. Switch to Star-Lord and shoot at the green ball in the Celestial:

To defeat the Celestial in level 1 of LEGO Marvel Super Heroes 2 shoot at the green ball in the Celestial.

Aim at the gravity mine and shoot the gravity mine into the Celestial:

To defeat the Celestial in level 1 of LEGO Marvel Super Heroes 2 throw a gravity mine into the Celestial.